Field of the Invention
The present invention relates to a rotatable-swingable input device that is disposed in an electronic apparatus including an image pickup apparatus, such as a digital camera, and an electronic apparatus equipped with the rotatable-swingable input device.
Description of the Related Art
There is an electronic apparatus, such as a digital camera, that is provided with a rotatable-swingable input device having an operation dial that allows a combined operation including swinging operations in a plurality of directions and a rotating operation. As a rotation detection means of the rotatable-swingable input device, a technique that detects rotation of an operation dial on the basis of a pulse signal that occurs by sliding a contact brush fixed to the operation dial along with an electrode pattern disposed on a printed circuit board is proposed (see Japanese Patent No. 5281589). In this proposal, when the operation dial is swung, a plunger disposed in the operation dial pushes a switch and a signal is output.
However, since the contact brush always slidably contacts with the electrode pattern when the operation dial is rotated, a continuous operation may wear the electrode pattern and deteriorate operability. Moreover, since wear of the electrode pattern destabilizes a contact state with the contact brush, there are problems in deterioration of an output signal and in durability. Furthermore, there is also a problem that resistance often varies according to the contact state between the contact brush and electrode pattern, which causes chattering, deteriorating reliability.
On the other hand, a technique that detects rotation of an operation dial by a magnet and magnetic field detecting element and that generates a click feeling magnetically by arranging another magnet opposite to the rotating magnet is proposed as a rotation detection means for a rotatable-swingable input device (see Japanese Patent No. 3820548). Since the magnet and magnetic field detecting element are non-contact in this proposal, the inconvenience mentioned above is canceled.
However, since the technique in the above-mentioned Japanese Patent No. 3820548 needs to magnetize a plurality of N poles and S poles to a magnetic substance in high accuracy, a cost increases. Moreover, since the click feeling is generated by magnetic suction and repulsion, it is difficult to obtain satisfactory operational feeling of the operation dial.
On the other hand, a technique that detects rotation of an operation dial using a transmission optical sensor and a shading blade that rotate together with the operation dial by counting shading parts of the shading blade that pass through a gap between a light projecting section and light receiving section of the transmission optical sensor is known as the rotation detection means. The rotation detection means using the transmission optical sensor is excellent in durability because the shading blade does not contact with the transmission type optical sensor, is compact because the shading blade is configured simply, and is configured at low cost because there is no need to use expensive parts.
However, when the transmission type optical sensor is used as the rotation detection means, and when the positional relationship between the shading part of the shading blade and the transmission optical sensor is not suitable in a stable position where the rotation of the operation dial stops, the rotation detection accuracy of the operation dial may be lowered.
For example, since variation of the fixed position of the shading blade to the operation dial or variation of the stable position of the operation dial destabilizes transmission and shading of the transmission optical sensor, the rotation amount and the rotation direction of the operation dial may be misdetected. Moreover, it is necessary to prevent misdetection even if the switch is pressed by swinging the operation dial at the stable position of the shading blade.